Ok. Here we go. When the rx7 is started after sitting it smokes like crazy until it's warmed up and sometimes the smoking stops and sometimes it doesnt. Sometimes it just lessens. The smoke is a thick billowing white. Spark plugs keep fouling. Oil pressure starts to go down real low around 10-15 but other times it seems fine. It is also not losing any oil or coolant.

Do not have a clue what this could be besides oil seals perhaps? Here is a little history on the car:

When we bought the car we were told there were 750cc primaries and a 3 inch straight through exhaust. Took it apart found out the injectors were nice and stock and measured the pipe finding out it was 2.5in no real problem there but still something that was lied about when we got the car. They also claim the engine was rebuilt....do not know how, who, when or where. But I tend to believe it hasn't been.

Besides taking it apart to look at the injectors. (put in new o-rings and such). New spark plugs. We have also done the following tests:
Did the check where you turn the car on cold and look for bubbles from the radiator. It passed. Compression checked out ok. Disabled the omp and running premix.

 

well if it actually does have 750's it would be running very rich, explaining the white smoke. Its possible that the stock injectors were re-bored to 750cc/min, altho thats usually not recommended (lower tolerances, greater variation from one injector to the next)